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Next Generation MITnet

April 19, 2017

To the members of the MIT community:

We are writing to inform you of plans to upgrade the MIT campus network, and in particular to upgrade MIT to the next generation of Internet addressing. (Please note that no action is required on your part.)

Machines on the Internet are identified by addresses. The current addressing scheme, called IPv4, was specified around 1980, and allowed for about 4 billion addresses. That seemed enough at the time, which was before local area networks, personal computers and the like, but the Internet research community recognized around 1990 that this supply of addresses was inadequate, and put in place a plan to replace the IPv4 addresses with a new address format, called IPv6. IPv6 uses a 128-bit address scheme and is capable of 340 undecillion addresses (340 times 10^36, or 340 trillion trillion trillion possible IP addresses). This stock of addresses allows great flexibility in how addresses are assigned to hosts, for example allowing every host to use a range of addresses to make tracking more difficult. With IPv6, we need not worry about the proliferation of smart phones, the Internet of Things, or whatever comes next.

While IPv4 is still the workhorse of Internet addressing, IPv6 is coming. All major operating systems and devices already support both IPv4 and IPv6. Many of the large Internet Service Providers are supporting IPv6, and major content providers are moving to support IPv6, and so it is time to upgrade the MIT network for the future and make our network IPv6-capable.

For most users, this upgrade will be transparent. Once we upgrade our network infrastructure, most computers will start using IPv6 addresses automatically as appropriate. We will have to make some upgrades to our infrastructure, and the plans for this are under way.

MIT’s excess IPv4 capacity

As we plan our migration to IPv6, it is appropriate for MIT to consider its own stock of IPv4 addresses. While the Internet is running out of addresses overall, MIT actually has a large surplus. MIT helped lead the development of the Internet from the 1970’s onward, and David Clark, a Senior Research Scientist at our Computer Science and Artificial Intelligence Lab (CSAIL) quickly saw the importance of these addresses and requested an early allocation of them, both to support research and eventually to support all of computing at MIT. We hold a block of 16 million IPv4 addresses.

Fourteen million of these IPv4 addresses have not been used, and we have concluded that at least eight million are excess and can be sold without impacting our current or future needs, up to the point when IPv6 becomes universal and address scarcity is no longer an issue. The Institute holds a block of 20 times 10^30 (20 nonillion) IPv6 addresses.

As part of our upgrade to IPv6, we will be consolidating our in-use IPv4 address space to facilitate the sale of MIT’s excess IPv4 capacity. Net proceeds from the sale will cover our network upgrade costs, and the remainder will provide a source of endowed funding for the Institute to use in furthering its academic and research mission.

Given the source of these new funds, we believe that MIT should use them, whenever possible, to support activities focused on the future of the Internet and the global cyber-infrastructure. Our intention is not only to advance our own agenda, but to help shape the future of the on-line world. For instance, non-technical issues are now shaping the future of the Internet as much as, if not more than, technical innovation. Because finding funding for research and education in these areas can be difficult, using MIT’s IPv4 proceeds to support such efforts could benefit all future Internet users. David Clark has agreed to lead an advisory group to assist us in determining how best to proceed with this effort. We will be asking the MIT community for suggestions and proposals.

Migration plan

Over the next twelve to eighteen months, IS&T will be upgrading MITnet equipment and architecture to enable support for IPv6 devices, hosts, and networks, as well as IPv4. IS&T will provide a building-by-building schedule for updating IP addresses of the Institute’s networked devices and hosts.